Currently, copper indium gallium (di)selenide, also known as Cu2InGa(S, Se)4 or CIGS; and cadmium telluride (CdTe) are the major materials developed for use in thin film solar cells. With regard to the CIGS material, the prices of indium and gallium are high. Due to increasing demand in recent years for indium tin oxide (ITO) for use in flat panel displays, the price of indium continues to increase. With regard to CdTe, cadmium is toxic and tellurium is quite rare.